This is a phase III, multicenter, randomized, double-blind study of indinavir sulfate (IDV) with open label zicovudine (ZDV) and lamivudine (3TC) in patients with CD4 counts < 200 and > 6 months of prior ZZDV experience. The study is designed to determine the clinical efficacy of IDV in subjects with advanced HIV disease who have had prior antiviral therapy.